A 6-Hour-Old Boy Is in the Newborn Nursery with Tachycardia

question 480

Multiple Choice

A 6-hour-old boy is in the newborn nursery with tachycardia.  He was born at 40 weeks gestation to a 30-year-old woman with Graves' disease that was treated with surgical resection approximately 6 months before the pregnancy.  Subsequently, the mother became mildly hypothyroid and was treated with levothyroxine during the pregnancy.  The infant's weight is 2080 g (4 lb 9 oz) (<5th percentile) , temperature is 37.2 C (99 F) , and pulse is 190/min.  Examination shows an irritable but consolable infant with warm, flushed skin.  Which of the following is the most likely cause of this infant's condition?

• A)Ectopic thyroid tissue
• B)Inadequate maternal surgery
• C)Increased TSH production
• D)Transplacental levothyroxine
• E)Transplacental TSH-receptor antibody

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